Out of the 915 unfed mosquitoes processed by PCR, eight pools of Cx pipiens from site C were positive for D. immitis, one in thorax/head pools and seven in abdomen-pools, corresponding to an estimated rate of infection (ERI) of 0.26% (95% CI 0.01-1.2) and of 2.07% (95% CI 1.03-4.11), respectively. After adjustment for mortality, the overall ERI for site C was 0.38%; this value was used to estimate the risk of exposure to a D. immitis infective Cx pipiens at the same site. Conversely, the risk of exposure to D. immitis at site B was calculated using the ERI recorded in a study performed 10 years later in the same area [11]. For site A no data on mosquito Dirofilaria spp. rate of infection is available.